Antenna



June 27, 1939. .w BERNDT 2,163,743

ANTENNA Filed Feb. 17. 1938 INVENTOR WALTER BERNDT ATTORNEY Patented June 27, 1939' PATENT OFFICE,

ANTENNA Walter Berndt, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphic in. b. 11., Berlin, Germany, a corporation of Germany Application February 17, 1938, Serial No. 190,917 In Germany February 18, 1937 6 Claims.

7 The present invention is concerned with a selfradiating antenna mast which is subdivided with a view to Obtaining a certain current distribution and which is electrically lengthened or loaded 6 at the break by means of series inductances. Ar-

rangements of this kind known in the earlier art involve thedrawback that the capacity between the mast end'swas high at the break 'or interruption point, with the result that the effect of the 10 inductance was impaired. In fact, one could never be sure whether the radio frequency current flowing in the outside of the mast actually passed through the coil or whether it might not be transferred capacitively to the other mast member. Another point was that the mounting of the series inductance was difiicult from a constructional viewpoint.

Now, these shortcomings are eliminated according to the present invention by disposing along the edges of the mast metallic ribbons or bars of material possessing a high degree of conductivity, and by inserting at the break of the masts, at each edge of the mast, an inductance optionally comprising a series system of several coils between the ends of the metal bands. Another object of the invention is to diminish the capacity between the two mast members by tapering the constituents of the mast to result in a conical point, the ends being thus of reduced cross-sectional area and spaced apart by a small insulator. This affords the further advantage that the coils may be freely suspended in the air and need thus not be attached by any special constructional means.

The invention shall be'described more fully by reference to the appended drawing in which Fig. 1 illustrates an embodiment of my invention and Fig. 2 an enlarged detail. Referring to Fig. 1, M1 is the bottom mast member, while M2 is the top part thereof. Both these parts of the mast are tapered to a point which is located preferably somewhat above the middle where they are spaced apart by means of an insulator I. The bottom member of the mast is supported and secured upon the base insulator IF. The top member of the mast is provided with a top capacity D in the form of a disk. Along the edges of the mast are metal ribbons or bars B through which the major part of the radio frequency current flows, since the said ribbons form the outermost portions of the cross-section of the mast, and since they consist moreover of material having a high conductivity. At the break between the two mast members are disposed the coils C1, C2, each thereof being subdivided into three partial coils. The

entire mast construction issupported by guy wires or cables A. Owing to the fact that both the bottom and the top member ofthe mast are tapered at their lower ends, conditions are made so that the whole mast construction is statically well defined; as a result, the structure is more readily constructed and requires fewer guy wires or cables. Also this feature distinguishes the present invention very advantageously from the arrange ments known in the prior art.

Fig. 2 shows to an enlarged scale the break between the mast members. U0 denotes the bottom end of the upper mast member, while Ou designates the top end of the bottom mast member. They are separated by the insulator I. It will be seen that the capacity between the two mast members is extremely low and that the same may be reduced to a minimum value by choosing a suitable shape for the insulator I. Along the edges of the mast are disposed the metallic bands or bars M; in Fig. 2 they are indicated only for one edge of the mast. These bands are suitably spaced apart from the mast by the aid of metallic spacers A. These bands or bars may consist of copper or of aluminum or some other metal possessing high conducting power. Directly suspended on the bands are the coils 0. They consist each of three parts, the same as shown in Fig. l. The inductances themselves are suitably accommodated inside a ceramic container which is fitted with a cover. The latter has a ring for the suspension of the entire container or pot. The uppermost subdivisional coil is directly suspended from the metal band M. Also, the coil is separately supported from the mast itself. The various subdivisional coils are interconnected by wire cables both mechanically as well as electrically; in order to preclude swaying of the whole coil arrangement, the latter is kept a fixed distance from the mast by the aid of supporting or pin insulators IA- The lower ends of the bottommost coil is preferably united with the metallic bar of the bottom mast member by means of a flexible conductor B. Also, at this point a pin type insulator IA is provided.

Fig. 2 clearly shows that the suspension of the coils is attended with no particular diificulties at all; also, that the mast structure itself is no impediment for the coils, contrary to what has been true of constructions known in the earlier art.

The invention is not confined to the exemplified embodiments here shown, in fact, quite a number of variations and modifications are conceivable. For instance, the inductances need not be split into a number of partial coils, in fact, they may construction, for all that is required is to fulfill the demand that the ends of the mast, at the break,

should be tapered into a cone so that a reduction of capacity between the two mast members is obtained. Also, the number of breaks to be bridged or bypassed by inductances may be chosen as desired.

I claim:

1. A self-radiating antenna mast comprising a plurality of aligned sections each of said sections having highly conductive members along thin edges, a loading inductance connecting each conductive member of one section to the conductive members of the adjacent section characterized in that the adjacent ends of the mast sections are tapered, and an insulator between each of said sections.

2. A self-radiating antenna mast comprising a plurality of aligned sections each of said sections having highly conductive members along thin edges, a loading inductance connecting each conductive member of one section to the conductive members of the adjacent section characterized in that the adjacent ends of the mast sections are tapered, and an insulator between each of said sections, and insulating supports for each of said loading inductances.

3. A self-radiating antenna mast comprising one or more breaks or points of interruption bridged or bypassed by inductances, with the characteristic feature that along the. edges of the V mast, metal bands or bars of high conducting material are disposed, and that at the break, at each edge of the mast, an inductance is arranged between the ends of the metal bands, the said inductance consisting of a series system of a plurality of coils.

4. Antenna mast as claimed in claim 3, with the characteristic feature that the ends of the two mast members are tapered at the break, and are insulated in reference to each other by means of an insulator.

5. Antenna mast as claimed in claim 3, with the characteristic feature that the coils consist of inductances confined inside ceramic pots.

6. Antenna mast as claimed in claim 3, with the characteristic feature that the coils are me- 

